For the operating of doors of above and similar kind up till now different solutions have been used. As an example may be mentioned power or motor devices which over appropriate transmission arrangements by means of belt or chain drives move the door and motor driven rollers which with constant force are pressed against a running path at the door so that they on rotation moves the door.
Known arrangements are because of their construction rather rigid and have small, in many cases no ability to give way and allow manual moving of the doors for instance on loss of electric power. For such reasons it occurs that you have to arrange special emergency operating devices so that the doors will not be blocked on interruption of electricity supply.
Doors of the kind mentioned above, both rotating and sliding ones, also require some sort of braking device in order to stop the movement of the door. At known operating devices the braking effect often is achieved in inductive way by short circuiting the driving motor or in a similar way.